Braking System of the Brake-By-Wire Type for Motorcycles

The present invention further relates to a braking system of the brake-by-wire (BBW) type, in particular for motorcycles.

In motorcycles, there are brake-by-wire type braking systems in which the user can manually operate two separate manual controls, typically a lever on the handlebar, and a pedal, so as to send a request for braking action to an appropriate control unit.

Such a request for braking action is switched to actuation of one or more electric motors acting on the friction elements (typically pads, but also shoes) of the braking devices with which the motorcycle is provided. Under normal operating conditions, the user thus does not directly command the actuation of the braking devices but sends a braking request which is met by said electric motors, by means of a control unit.

In case of a malfunction, the system must allow a hydraulic back-up to ensure that the user can at least partially brake the motorcycle by means of direct action on the manual operating devices.

The motorcycle solutions of the prior art do not allow operating the hydraulic back-up by means of both controls (lever and brake pedal) in case of failure of the E/E system (ECU, actuators, sensors, etc.) or in case of lack of power supply (disconnected battery) combined with the need to have a partially fluid-free brake system actuation (at least one fully electromechanical caliper or axle—DRY). Finally, the need is felt to provide braking systems being compatible with electric vehicles (blending with regenerative braking, residual torque reduction).

The need is thus felt in the art to provide a braking system which allows solving the technical problems mentioned with reference to the prior art.

The need is met by a braking system according to claim.

In particular, such a need is met by a braking system for a motorcycle comprising a first braking device operatively connectable a to first wheel of the motorcycle, and provided with a first hydraulic supply circuit, first manually operated hydraulic device provided with a first manually operated control and a first hydraulic delivery circuit fluidly connectable to the first hydraulic supply circuit, a second braking device operatively connectable to said first wheel or to a second wheel of the motorcycle, and provided with a second hydraulic supply circuit, distinct from or coinciding with the first hydraulic supply circuit, a second manually operated hydraulic device provided with a second manually operated control and a second hydraulic delivery circuit fluidly connectable to the second hydraulic supply circuit, an electric actuator having electric or electromechanical motor means operatively connected to an electrically or electromechanically operated float fluidly connected to a delivery of the electric actuator connected to said first hydraulic supply circuit and/or said second hydraulic supply circuit, where said first and second hydraulic delivery circuits are fluidly connected to each other by the interposition of valve means, where the braking system is provided with a processing and control unit, operatively connected to said electric actuator and said valve means, the processing and control unit being programmed so that: in standard operation, in case of actuation of the first manually operated hydraulic device and/or the second manually operated hydraulic device, it translates the electrically or electromechanically operated float so as to fluidly disconnect the first and/or second hydraulic supply circuit from the first and/or second hydraulic delivery circuit and simultaneously actuate the at least a first braking device and/or the at least a second braking device.

According to a possible embodiment of the present invention, the processing and control unit is programmed so that: in back-up operation, it backs up or allows the backing up of the electrically or electromechanically operated float so as to allow the fluid connection between the first and/or second hydraulic supply circuit from the first and/or second hydraulic delivery circuit and simultaneously actuate the at least a first braking device and/or the at least a second braking device, when at least one of the first and second manually operated hydraulic devices is operated.

According to a possible embodiment of the present invention, said valve means comprise a diverter valve having a first inlet port, fluidly connected to the first hydraulic delivery circuit, a second inlet port fluidly connected to the second hydraulic delivery circuit, and a single outlet port in fluid communication with the hydraulic delivery circuit, between said first and second hydraulic delivery circuits, having greater pressure.

According to a possible embodiment of the present invention, the first hydraulic delivery circuit is provided with at least one control valve, which in standard operation connects the first hydraulic delivery circuit to a first hydraulic braking simulator, and in back-up operation, connects the first hydraulic delivery circuit to the first inlet port of the diverter valve, and/or where the second hydraulic delivery circuit is provided with at t least one control valve, which in standard operation connects the second hydraulic delivery circuit to a second hydraulic braking simulator, and in back-up operation, connects the second hydraulic delivery circuit to the second inlet port of the diverter valve.

According to a possible embodiment of the present invention, the first manually operated device is provided with a first hydraulic fluid tank having a preloaded membrane which ensures an overpressure to compensate for a different geodetic height with respect to a second hydraulic fluid tank of the second manually operated device.

According to a possible embodiment of the present invention, said valve means comprise a slide valve controlled by the processing and control unit so that: in the standard condition, the slide valve fluidly separates the first hydraulic delivery circuit, the second hydraulic delivery circuit, and the delivery of the electric actuator from one another, where said delivery supplies said first and second hydraulic supply circuits, in back-up mode, the slide valve puts into communication the first hydraulic delivery circuit with the first hydraulic supply circuit, and the second hydraulic delivery circuit with the second hydraulic supply circuit, and where the slide valve hydraulically separates the first and second hydraulic supply circuits.

According to a possible embodiment of the present invention, the system comprises a main hydraulic fluid tank, which supplies a first tank of the first manually operated hydraulic device and a second tank of the second manually operated hydraulic device, where said main tank is preloaded, and where said preload is such as not to generate a pressure which results in an actuation of the braking devices, where said valve means comprise a slide valve which selectively connects or disconnects the first and second hydraulic delivery circuits to/from the first and second hydraulic supply circuits, respectively.

According to a possible embodiment of the present invention, the system comprises a first hydraulic braking simulator connected to the first hydraulic delivery circuit and second a hydraulic braking simulator connected to the second hydraulic delivery circuit, each of said hydraulic braking simulators being provided with a single hydraulic tank, where said valve meanscomprise a slide valve which selectively connects or disconnects the first and second hydraulic delivery circuits to/from the first and second supply circuits, respectively.

According to a possible embodiment of the present invention, said slide valve is divided into four two-way valves, preferably two normally closed valves and two normally open valves.

According to a possible embodiment of the present invention, the system comprises a single brake fluid tank, which supplies the first and second hydraulic delivery circuits, upstream of said valve means, said single tank being preloaded under pressure.

According to a possible embodiment of the present invention, the first and second hydraulic supply circuits are fluidly connected to two braking devices arranged at the front of the vehicle.

According to a possible embodiment of the present invention, the first and second hydraulic supply circuits are coincident and fluidly connected to a single braking device at the rear of the vehicle.

According to a possible embodiment of the present invention, said first and second manually operated hydraulic devices are arranged mutually in series and in series with the first and second hydraulic supply circuits, where each manually operated hydraulic device comprises a piston provided with a one-way lip seal at the outlet of the device itself.

According to a possible embodiment of the present invention, the system comprises a brake fluid tank connected directly upstream of the electric actuator by means of a plurality of series of one-way valves which allow the leakage of fluid with the system at atmospheric pressure while preventing the passage in the opposite direction during the actuations of the braking devices in both standard operation and back-up operation.

According to a possible embodiment of the present invention, said valve means comprise two normally open hydraulic valves which fluidly connect both the manually operated hydraulic devices and two normally closed hydraulic valves to allow the passage of pressure between said manually operated hydraulic devices and the hydraulic supply circuits and prevent the absorption of volume by absorbers connected to the manually operated hydraulic devices in back-up.

According to a possible embodiment of the present invention, said braking devices comprise disc brakes and/or drum brakes.

The present invention further relates to a motorcycle comprising a braking system as described above.

The elements or parts of elements common to the embodiments described below will be indicated by the same reference numerals.

With reference to the aforesaid figures, reference numeralindicates as a whole a braking system for a vehicle, in particular for a motorcycle.

The braking systemfor motorcyclecomprises a first braking deviceoperatively connectable to a first wheel (not shown) of the motorcycle, and provided with a first hydraulic supply circuit. Typically, the first braking devicecan comprise a disc brake or a drum brake.

The braking systemcomprises at first manually operated hydraulic deviceprovided with a first manually operated control, such as a lever or a pedal, for example, and a first hydraulic delivery circuitfluidly connectable to the first hydraulic supply circuit.

The braking system further comprises a second braking deviceoperatively connectable to said first wheel or to a second wheel (not shown) of the motorcycle, and provided with a second hydraulic supply circuitdistinct from or coinciding with the first hydraulic supply circuit.

Typically, the second braking devicecan comprise a disc brake or a drum brake. The second hydraulic supply circuitcan be physically distinct from the first hydraulic supply circuit, but it can also converge into the first hydraulic supply circuitso as to coincide therewith.

The braking systemcomprises a second manually operated hydraulic deviceprovided with a second manually operated control, typically a lever or a pedal, and a second hydraulic delivery circuitfluidly connectable to the second hydraulic supply circuit.

The braking systemfurther comprises an electric actuatorhaving electric or electromechanical motor meansoperatively connected to an electrically or electromechanically operated floatfluidly connected to a deliveryof the electric actuatorfluidly connected to said first hydraulic supply circuitand/or said second hydraulic supply circuit.

Typically, the deliveryis a hydraulic fluid conduit, which fluidly converge into the first hydraulic supply circuitand/or the second hydraulic supply circuit.

Advantageously, said first and second hydraulic delivery circuits,are fluidly connected to each other by the interposition of valve means, better described below.

The braking systemis provided with a processing and control unit, operatively connected to said electric actuatorand said valve means, which is programmed so that, in standard operation, in case of actuation of the first manually operated hydraulic deviceand/or the second manually operated hydraulic device(with which the user requires a braking action from the system), it translates the electrically or electromechanically operated floatso as to fluidly disconnect the first and/or second hydraulic supply circuit,from the first and/or second hydraulic delivery circuit,and simultaneously actuate the at least a first braking deviceand/or the at least a second braking device.

According to an embodiment, the processing and control unitis programmed so that, in back-up operation, it backs up or allows the backing up of the electrically or electromechanically operated floatso as to allow the fluid connection between the first and/or second hydraulic supply circuit,and the first and/or second hydraulic delivery circuit,and simultaneously actuate the at least a first braking deviceand/or the at least a second braking device, when at least one of the first and second manually operated hydraulic devices,is actuated.

According to a possible embodiment (), said valve meanscomprise a diverter valvehaving a first inlet port, fluidly connected to the first hydraulic delivery circuit, a second inlet portfluidly connected to the second hydraulic delivery circuit, and a single outlet portin fluid communication with the hydraulic delivery circuit, between said first and second hydraulic delivery circuits,, having greater pressure.

It is thus possible to brake using both manually operated lever or pedal controls and that delivering the most pressure, i.e., that on which the user applies the most pressure (whether the pedal or the lever) prevails, in terms of actuation pressure.

According to a possible embodiment of the present invention (), the first hydraulic delivery circuitis provided with at least one control valve, of the NO (normally open) or NC (normally closed) type, which in standard operation connects the first hydraulic delivery circuitto a first hydraulic braking simulator, and in back-up operation, connects the first hydraulic delivery circuitto the first inlet portof the diverter valve, and/or where the second hydraulic delivery circuitis provided with at least one control valve(of the NO or NC type), which in standard operation connects the second hydraulic delivery circuitto a second hydraulic braking simulator, and in back-up operation, connects the second hydraulic delivery circuitto the second inlet portof the diverter valve.

According to a possible embodiment (), the first manually operated deviceis provided with a first hydraulic fluid tankhaving a preloaded membrane which ensures an overpressure to compensate for a different geodetic height with respect to a second hydraulic fluid tankof the second manually operated device. The problem of emptying the tank placed at a higher elevation, typically in motorcycles, is thus solved, this being the tank connected to the handlebar lever, elevated above the tank connected to the pedal.

According to a possible embodiment (), the valve meanscomprise a slide valvecontrolled by the processing and control unitso that, in the standard operating condition, the slide valvefluidly separates the first hydraulic delivery circuit, the second hydraulic delivery circuit, and the deliveryof the electric actuatorfrom one another, where said deliverysupplies said first and second hydraulic supply circuits,.

Moreover, in back-up mode, the slide valveputs into communication the first hydraulic delivery circuitwith the first hydraulic supply circuit(which controls a first caliper mounted to the front wheel of the motorcycle, for example), and the second hydraulic delivery circuitwith the second hydraulic supply circuit(which controls a second caliper mounted to the same front wheel of the motorcycle, for example), and where the slide valvehydraulically separates the first and second hydraulic supply circuits,. By virtue of this hydraulic separation, the hydraulic circuits of the two manual controls for the rider are mutually independent, thus avoiding the action of one from biasing the characteristic of the other.

According to a possible embodiment (), the braking systemcomprises a main hydraulic fluid tankwhich supplies a first tankof the first manually operated hydraulic deviceand the second tankof the second manually operated hydraulic device, where said main tankis preloaded. Said first and second tanks,cannot be emptied because of the difference in the respective geodetic height. Preferably, said preload, e.g., obtained by means of a membrane biased by a spring, is such as not to generate a pressure which results in an actuation of the braking devices,. Preferably, said valve meanscomprise a slide valvewhich selectively connects or disconnects the first and second hydraulic delivery circuits,to/from the first and second hydraulic supply circuits,, respectively.

According to a possible embodiment (), the braking systemcomprises a first hydraulic braking simulatorconnected to the first hydraulic delivery circuitand a second hydraulic braking simulatorconnected to the second hydraulic delivery circuit, each of said hydraulic braking simulators,being provided with a single hydraulic tank. Preferably, the valve meanscomprise a slide valvewhich selectively connects or disconnects the first and second hydraulic delivery circuits,to/from the first and second supply circuits,, respectively. The free fluid bed is thus above everything else in the hydraulic circuit, whereby no preload is needed to avoid emptying across different tanks. Furthermore, in this configuration, non-return valves are also unnecessary since the tank is placed upstream of all pumps.

According to a possible embodiment (), said slide valveis divided into four two-way valves, preferably two normally closed (NC) valves and two normally open (NO) valves.

According to a possible embodiment (), the systemcomprises a single brake fluid tankwhich supplies the first and second hydraulic delivery circuits,, upstream of said valve means, said single tankbeing preloaded under pressure (so as to ensure complete filling of the manual controls, whether a lever or a pedal, as a result of thermal expansion and pad wear, in both standard and back-up modes.

The absence of separate tanks provided on each manually operated hydraulic device,allows two functions. In back-up operation, it allows a pressure generation, e.g., by the pedal, and also pressurizes the manual lever control at rest, which would not be possible with a tank at ambient pressure. Moreover, the manually operated control, in particular the brake lever, is particularly aesthetically minimal, making the style of these components particularly innovative and unique.

For example (), the first and second hydraulic supply circuits,are fluidly connected to two braking devices,arranged at the front of the vehicle.

An embodiment () is also possible, in which the first and second hydraulic supply circuits are coincident and fluidly connected to a single braking device arranged on the rear wheel of the motorcycle.

According to a further possible embodiment (), said first and second manually operated hydraulic devices,are arranged in series with each other and with the first and second hydraulic supply circuits,. Each manually operated hydraulic device,comprises a piston provided with a one-way lip seal (not shown) at the outlet of the device. It is thus possible to control a single caliper with both manually operated controls,according to a maximum logic.